The X-ray diffraction data to 2.7 Angstroms for McPc603 Fab have been collected and processed. The structure has been partially refined at this resolution. X-ray diffraction data have been collected and processed to 2.5 Angstrom resolution for the Mouse galactan-binding myeloma protein J539 Fab. Crystals obtained from Weaver Fv, a human IgM with specific binding for pyruvylated-D-galactose, have been shown to transform to a higher symmetry when exposed to solutions of K2Pt(CNS)6. This symmetry implies that the unit cell contains either the VH or VL but not both.